Question

Решите 169,171,174
Дам 50 баллов

Answer 1

$169)\; \; (1-log_456)(1-log_{14}56)=(log_44-log_456)(log_{14}14-log_{14}56)=\\\\=log_4\frac{4}{56}\cdot log_{14}\frac{14}{56}=log_4\frac{1}{14}\cdot log_{14}\frac{1}{4}=log_414^{-1}\cdot \frac{log_4\frac{1}{4}}{log_414}=-log_414\cdot \frac{-1}{log_414}=1$

$171)\; \; log_{\sqrt[8]{14}}\, 14=log_{14^{1/8}}\, 14=\frac{1}{1/8}\cdot log_{14}14=8\cdot 1=8\\\\\\174)\; \; log_{1,25}\, 7\cdot log_7\, 0,8=log_{\frac{5}{4}}\, 7\cdot log_7\frac{4}{5}=log_{(\frac{4}{5})^{-1}}\, 7\cdot log_7\frac{4}{5}=\\\\=-log_{\frac{4}{5}}\, 7\cdot log_7\frac{4}{5}=-\frac{1}{log_7\frac{4}{5}}\cdot log_7\frac{4}{5}=-1$

Answer 2

Ответ: во вложении Объяснение: